split or combine turbulent fluxes?

[juliasloan25]

ClimaLand recently changed their turbulent fluxes to separately store SHF and LHF. ClimaAtmos currently just provides one combined turbulent fluxes field. We should choose one of these conventions to follow and use it throughout CliMA.

Currently, to adapt between these two approaches, the bucket SHF gets updated with the combined turbulent fluxes from Atmos, and bucket LHF is zeroed out.